IV 



HEARING— GENERAL 



At the risk of appearing repetitive it may be as well to 

 remind students that the senses of animals must not be 

 viewed anthropomorphically. We think of hearing in our- 

 selves as a means of perceiving and interpreting sounds we 

 hear in an intelligent way — once we have passed the infant 

 stage. The spoken word, which is the great barrier between 

 the human animal and the wild animal, is translated by our 

 brains in such a manner as to convey to us the meaning of 

 these sounds as language. Other sounds ranging from gunfire 

 to the songs of birds are also interpreted intelligently accord- 

 ing to the degree of intelligence with which age, education 

 and civilization endows us. 



Among wild creatures the sounds they make are certainly 

 methods of communication with others of their own kind, 

 and are perceived as warnings of danger and so on. But this 

 does not mean the same thing as conversation which must 

 imply a degree of intelligence lacking even in the higher 

 groups of animals. 



It may be argued that our dogs are capable of learning 

 and responding to many words and short phrases in the 

 course of their training; but of course no dog interprets 

 these words as would a human being : it is the general sound 

 of such words that make a dog respond and, even more 

 important, it is the tone of voice in which we utter these 

 words that conveys to the dog what it is required to do. 



The scientific and technical side of hearing will be fully 

 treated in Part II by Dr. Harrison Matthews; but a brief 

 reference to the nature of sounds will not be out of place 

 here. 



All sounds are caused by vibrations of widely differing 



frequencies both through the air, the earth, and in water; 



and the many types of animals are adapted, according to 



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